Thomas Forrest, a British ship captain who explored Mindanao in the 1770 mentioned Cagayan in his book printed in 1780.
Forrest mentioned the old Cagayan in May 1775 in his book titled “A Voyage to New Guinea and the Moluccas”. Below is a screen capture of page 199 of the 411-page book.
Clearly, Forrest saw the old Cagayan fort which is made of stone. The page above is in Book 2, Chapter 3. Download it HERE. (right click, “Save As”)
info taken from article by Paulita Roa HERE.